I'm not understanding how to groupby on a large df in R
Columns 0-12 are identifiers, unique, and I would like to leave them as is
I've tried a number of variations of this
aggregate(cbind(names(preferences[-c(0,12)]))~cbind(names(preferences[c(0,12)])),data=preferences,FUN = sum)
I'm getting Error in model.frame.default(formula = cbind(names(preferences[-c(0, 12)])) ~ : variable lengths differ (found for 'cbind(names(preferences[c(0, 12)]))')
a b c d e
1 f(1) 11 2 15
1 f(1) 12 2 15
2 f(2) 13 4 3
2 f(2) 14 6 4
3 f(3) 15 5 6
a b c d e
1 f(1) 23 4 30
2 f(2) 27 10 7
3 f(3) 15 5 6
Python equivalent df[11:624].groupby(by=col11)
df is 48GB so speed matters (python crashes due to a lack of memory(250GB))
After receiving an answer I went and looked at some benchmarks and this is fast as heck!!!!
CodePudding user response:
library(data.table)
setDT(df)
x <- names(df)[13:ncol(df)]
y <- names(df)[1:12]
df_2 <- df[, lapply(.SD, \(i) sum(i)), .SDcols=x, by=y]
Though be aware of indexing in R vs Python. R starts counting from 1 (whereas Python has zero indexing)